Split pulley



H. J. GlLBr-:RT

\SPLIT PULLEY Filed July 21, 1924 :s sheets-sheet 2 1ML l 7 Aug. 28,1928. 1,682,559

H. J. GILBERT SPLIT PULLEY Filed July 2l, 1924 a '3 Sheets-Sheet 3 SM@1mm-u Patented Aug. 28, 1928.

UNITED STATES 1,682,559 PATENT OFFICE.

HENRY J. GILBERT, OF SAGINAW, MICHIGAN, ASSIGNOR T SAGINAW MANUFAC-TUBING CO., 0F SAGINAW, MICHIGAN, A CORPORATION.

SPLIT PULLEY.

Application med July 21, 1924. serial No. 727,285.

This `invention relates to splitI pulleys. The Vimprovement pertains tocertain novel constructions and combinations of parts whereb a ulley isproduced that complies with a ofp the following requirements of service:lighter weight, increased strength to resist stresses caused by beltpull and shaft torque, better coaxial alinement of the rim and shaft,improved running balance, avoidance of sidewise wabbling or weaving ofthe y rim when in motion, avoidance of flat places in the pulley facebetween the spokes, and rim bulges at the ends of the spokes, moreeffective hub grip on the shaft, a hub construction that renders allbolts easily accessible for tightening, and `a rim construction thatsecures freedom from objectionable internal strains in the spokes andhub, as well as in the rim itself.

Another object of my invention is to produce a pulley adapted to rapidand economical quantity production in various diameters and widths,conforming to a new scheme or stand- `ard unit lan of split pulleyconstruction.

With t e foregoing and certain other objects in view which will appearlater in the specifications, my invention comprises the devicesdescribed and claimed and the equivalents thereof.

In the drawings, Fig. 1 is a perspective view of' a pulley embodying myimprovements.

Fig. 2 is a fragmentary detail of the rim and a spoke separated.

Fig. 3 is a rspective view of one half a v pulley embodying two sets ofspokes and hubs.

Fig. 4 is an enlarged longitudinal section through a half hub.

Fig. 5 is a side view showing the hub and spokes, the rim removed.

Fior. 6 is a detail of a modified form of riveting ear for the rimreinforcing rib.

Fig. 7 is a further modified form.

Fig. 8 is a section through the hub in the plane of the clamping bolts.

Fig. 9 is a side view of the hub.

In carrying out my invention I employ the usual elements of a splitpulley, namely, a sheet metal rim, spokes, a hollow shell-like splithub, and clamping bolts. I have made improvements in those variouselements, and my present invention resides in the novel construction andcombinations of the improved related parts.

Referring to the drawings, 1 is the split rim, preferably formedpofsheet metal and having an internal reinforcing rib 2 integral therewith.

Ears 3 on the rib 2 constitute riveting lugs for the spokes and areimportant features of my improved pulley. They have to do with theaccuracy of the pulley, its strength, and freedom from rim strains, aswill appear later.

The hub, both as to its construction and its mode of operation ingripping the shaft has novel features that form an important part of thepulley as an operating unit. It is made in two parts 4, 5, eachcomprising, as shown in Figs. 3 and 4, a pair of collars orshaft-gripping members 6, 7, spaced apart lengthwise as at 8. Athin-walled housing 9, preferably of U-sliaped cross section connectsthe members 6 and 7.

The hub housing 9 has spoke-receiving faces 12 on its outer wall. Thesefaces are in line with the respective riveting lugs 3 on the rim, asindicated in Fig. 4 by dotted line 13-13. A straight spoke 14, whenfitted to an ear 3 at one end will lie flat on the corresponding face 12of the hub at the other end. The spoke, therefore, can be applied andriveted or otherwise secured at both its ends 157 16, without having tobe forced or sprung into place, and without setting up any twisting) orbending strains in the rim or in the Hub members 4 and 5 are clampedupon the shaft, not shown, by the usual bolts 10, 11.

Heretofore when a pulley has been located with one side close to a wall,a post or a shaft bearing, access to the bolt on that side was diiicultif the adjacent heads or nuts were in the same plane on the hub. Inconsequence it has frequently happened that the hub has not beenproperly tightened on the obstructed side and slippage of the pulley onits shaft, with consequent wear and damage has resulted. My improvedarrangement of the boltseats on the hub, which willnow be described,avoids this difficulty by making it easy to tighten all the bolts.

Each hub section 4, 5 has two or more-apertured seats 17, 18 thatreceive the clamping bolts 10, 11. As shown in Figs. 1 and 5, the seatsare offset or stepped so the nut or head of one bolt, as 10, is seatedabove the head or nut of the adjacent bolt 11. Consequently it can beturned by an ordinary wrench worked from either side of the pulley andthe end of the adjacent bolt can not i11- ico ' Consequently a twospokes are arranged convergent and se .clamping I hub at place as closeas possible tothe shatt, the tendency to spring or terfere with thewrench. .In Fig. 8, sheet 2, one of the bolts, as 10, has its raisedseat in staggered relation to seat 17 on the opposite hub member 5,thereby making the nuts of both bolts equally accessible. i'

The hub clamping bolts are arrangedclose to the shaft opening and in thespace between the gripping collars 7, 8. y This arrangement permits asmaller hub to be employed, yet the shaft is gripped tighter with lessresultant strain on the hub housing. In Figs. 3 and 9, 10 and 11 are theholes for boltslO and 11, located 4between v. the two longitudinallyspaced shaft-gripping members (i and 7 rl`hc bolt holes are very closeto the bore ot the hub, as shown'in Fig. 9.A Since the whole force ofthe bolts is applied to the bend the hub housing when holting up isthereby reduced.

hub of relatively light construction can exert great gripping pressureupon the shaft, and in a most direct and effective way. The offset boltarrangement above referred to is described and claimed in my co-pendingapplication, Serial No. 727,- 284. i

Within the hollow shell or lhousing 9 and in thespace 8 between theclamping members `G and' there is ample room for manipulatlng aholding-on tool while the spoke rivets 16` are being driven.

The spokes 14 are spaced around the huh and rim, see Fig. 5, so as notto hinder access to the. heads and nuts of all the bolts from .eitherside of the pulley. Preferably the spokes are cut to length fromstraight rolled bars of suitable cross section,.altl iough they may bemade from sheet metal folded to the desired section. i'

A'The form ofspoke-section'shown in Fig. 2

vis well adapted to exert maximum resistance against bending in anyplane. 'It also has relatively largeV riveting area, y yet minimumwidth, and its air resistance 1s negligible.

Various spoke arrangementsmay be adopt-k ed. For example, if a singlerib 2 is used `cured at their outer ends tothe same ear, as

in Fig. l. The spread of the spokes meas- Y urcd along the axis of theshaft, as at 8, Pig.

et,V is by this arrangement as wide as possible.

the spokes and hub together having maximum width of base for a givenlength of` hub. Thereby all tendency to weave 1s eliminated and lateralstiffness is imparted to the pulley.

Extra strong pulleys designed for very wide belts preferably employ twoor more structural units, Fig.y 3, each comprising a il hub and spokes.Obviously any number of f such units may be used to make a pulley of anydesired Width efface.

The rim 1 and the purpose of its reinfore- V`by making the ribs 2narrow, that is, of merely sulhcicnt depth to provide the necessaryining rib 2 withears 3 thereonxwill now be described.

It has been customary heretofore to make the reinforcing ribs ofconsiderable depth radially so as to give suflicient support for the rim1, and also to provide adequate riveting area for allixing the spokes.But ribs of any considerable depth have certain serious disadvantages.For example, when the sheet metal rim 1, having been folded to propercross-sectional shape is rolled or pressed into ascnii-circle, the inneredge of themrib 2 is decreased in circumference and is lsubjected. tocompression. Ifpthe rib 2 is deep this results in the forcibledistortion of the rib by vH0 forming crinkles or corrugations along itsedge as shown at 2 in Fi l. Objcctionable internal strains are thernyset up in rim l, as evidenced bythe distortion of the edge of. the rib.Strains of that kind are serious because they weaken the rim and producein it an ever-present tendenc todeform or twist out of shape. Theyreduce the strength of the assembled pulley so that it is likely to,fail even when subJcctcd to working loads well within the safety factorfor which it was originally designed.

'lhe usual practice has been to correct the rib deformation byforciblytlattening the crinkles 2 in subset ucnt die-forming or' pressingoperations. liut instead of relieving the stresses already produced,other and even more severe internal strains are thereby set up in therim l. M

Even if a deep rib does not actually crinkle when the rim is rolled toshape it will nevertheless cause stresses and faults `in the riin l. Theinternal stresses, Aof which crinkling is the visible evidence, can .belargely avoided terior support for the rim. That, however, entailssacrificing some of the riveting area necessary to accommodate thenumber of rivets required at the spoke ends. GiissetV plates and variousother erpedients, as for example, widely forked or flattened spoke ends,have been applied to narrow or shallow ribs in an attempt to secure therequisite riveting y area, but such constructions involve a large amountof work and introduced inaccuracies of alinenient aswell as internalstrains in the spokes andrim. It is a purpose of my improved ribconstruction to avoid those defects, yet secure allthe advantages ofyadeep rib. han

I make that part of the internal rib 2 between the spokes ofmoderatedepth, suili cient to give adequate rim support between thespokes, vet shallow enough to avoid appreciable crinkling, and at thepoints of attachment of the spokes to the rim the de )th of the rib isincreased to form ears 3. 'he length of ear 3, measuredcircumferentially,

is approximately equal `to thc ,width of a great degree whenthe rim isbeing formed to semi-circular shape, and such crinkling tendency as doesdevelop is relieved preferably by being diverted to the forming of oneor more radially disposed laterally projecting ridges, 3a, on the faceof each ear 3.

The relief afforded by the ridging or bulging of the ear at 3 obviouslyprevents the development of undesirable internal stresses in the rim atthat point. Consequently the rim can be rolled as truly circular at theears 3 as it is between the spokes 14. The ridge 3 also may be utilizedto lock the spoke aga-inst sdewise movement, the spoke itself beingpreferably formed with a longitudinal groove 3b to receive the ridge 3*.

Various means may be employed to provide the relief above referred toand thereby prevent undesirable reactionary buckling or bulging stressesin the rim where the ears 3 are located.

In Figs. 2, and 7 I have shown three of the Ways in which this resultmay be accomplished. In Fig. 2 the ridge 3a is started by forming anincipient bulge in ear 3 before the rim is rolled to its final circularshape. rIhe compression of the metal in ear 3 produced by bending therim results in further bulging at 3 land consequent relief of theinternal strains that would otherwise be set up in the rim.

In Fig. 7 the ear 3 is apertured as at 3d before the rim is bent toshape. This removal of metal relieves or prevents the establishing ofcompressive strains within the ear 3 and in the absence of such strainsthe rim can be rolled true and smooth. The strength of the ear is notharmfully reduced by the aperture 3d, be 'fa use the spoke end whenriveted to the ear provides the requisite amount of reinforcement. InFig. G a small area on ear 3 has been made thinner by grindiniT orotherwise at 3c, prior to rolling the rim. Abulge formed in this case,as in 3 of Fig. 2. The effect of reducing at 3C is similar to thatobtained by preliminary bulging.

By the means herein set forth true running ulleys of great strength,with rims Vfree rom inherent tendency .to spring or deform are produced.No harmful internal strains are set up in the hubs or spokes when theparts are riveted together, because no prying or springing is resortedto and no distortion occurs during the operations of forming, assemblingand riveting.

Standardization of parts is rendered pos sible by my invention, whichmakes it feasible to keep a supply of straight bars of spoke material instock, from which to cut spokes to length as needed. A single hubpattern supplies the hubs for several sizes of pulleys. The spokerequirements of a considerable range of pulley sizes is satisfied bymerely va ing the number of spokes.

'1I-lille full strength of material in rim and spokes is available toperform useful work because the non-crinkling rib 2 and the relievedintegral ears 3 eliminate all objectionable internal stresses.Consequently the spokes and rim, as well as the hub, can be lighter forgiven duty and safety factor.

Pulleys made as herein described are truly circular and coaxial with theshaft and have correct running balance because the rim assumes truecircular shape when rolled, whereas pulleys in which severe internalstrains are set up during the rim-forming operation or during the spokeassembling and riveting operations almost invariably have iiat placesand bulges in their rims.

Since there are no internal strains tending to throw the rim and spokesout of alinement, absence of weaving or wabbling is an especiallynotabie characteristic of these pulleys. The stepped and lengthwiseoffset bolt arrangement and the location of the spokes with relation tothe bolts makes the nuts and bolt heads so readily accessible thatnothing short of negligence will account for a hub improperly clamped toits shaft. Consequently in practice slippage of the hub on the shaftalmost never occurs when these pulleys are used.

llhe broader aspects of the combination of devices that comprises thecompleted pulley are described and claimed herein, and the specificimprovements in the various elements are set forth and claimed incertain of my copending applications.

Having thus described my invention what I claim and desire to secure byLetters Patent is:

l. A pulley comprising half-rims, each formed of a single piece offolded sheet metal rolled to semi-circularshape and having an internalrib of shallow radial depth and inwardly projecting ears integral witheach rib, a pair of hub sections each comprising two shaft-grippingmembers spaced apart lengthwise7 a housing consisting of a hollowannular shell of U-shaped section connecting said members, crampingbolts through said hub sections at places intermediate said spacedgripping members and located in longitudinally oflset relation,spoke-receiving faces on the outer walls of said housing, each facedisposed in a plane that includes one of said ears, and spokes, eachsecured at its outer end to one of said ears and at its inner end to oneof said spoke-receiving faces.

2. A pulley, comprising a rim and a hub, an inwardly projecting rib onsaid rim, a radial ridge in said rib, a spoke connecting Said hub andrim, and said spoke having a channel disposed longitudinally thereof tosnug y receive said ridge, and fastening means for said spoke and rib.

In testimony whereof, I affix my signature.

HENRY J. GILBERT.

